Effect of Perfusate Volume on Amikacin Concentrations Following Saphenous Intravenous Regional Limb Perfusion in Standing, Sedated Horses. Jurek K, Schoonover MJ, Williams M, Rudra P. Oklahoma State University, Stillwater, OK.
Volume of perfusate for intravenous regional limb perfusion (IVRLP) has been investigated in the equine forelimb but no published studies evaluate perfusate volume in the hindlimb. The objective of this study was to determine if perfusate volume influences synovial fluid amikacin concentrations achieved in the joints of the hindlimb during standing saphenous IVRLP with 1 g of amikacin. We hypothesized that the amikacin concentration achieved in the tarsocrural joint (TCJ), metatarsophalangeal joint (MTPJ), and distal interphalangeal joint (DIPJ) at 15 and 30 minutes would not be affected by perfusate volume. Saphenous IVRLP with 1 g of amikacin diluted with 0.9% NaCl to volumes of 10, 60, and 120 mL was performed in six standing horses in a cross-over design. Synovial fluid from the TCJ, MTPJ and DIPJ was sampled at 15 and 30 minutes following perfusate administration (before tourniquet release). Concentrations of ≥ 40 g/mL and ≥ 160 g/mL were considered therapeutic for susceptible and resistant pathogens, respectively. Synovial fluid amikacin concentrations observed were not different between volumes (P = 0.4). All concentrations were higher at 30 minutes compared to 15 minutes (P = 0.003). All median concentrations at 30 minutes were > 40 g/mL using the 60 mL and 120 mL volumes. Only the DIPJ achieved this concentration using the 10 mL volume. All median concentrations observed were < 160 g/mL for all volumes. Limitations include small sample size and use of normal horses. Perfusate volumes of 10–120 mL results in similar synovial fluid amikacin concentrations following saphenous IVRLP with 1 g of amikacin. Concentrations considered therapeutic for resistant pathogens may not be achieved.